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Identification of a novel multifunctional oxidosqualene cyclase from Zea mays sheds light on the biosynthetic pathway of three pentacyclic triterpenoids

Zea mays (maize) is an important agricultural crop that produces a variety of valuable terpenoids, including several triterpenoids. However, no oxidosqualene cyclase (OSC) enzymes, which catalyze the first step in triterpenoid biosynthesis, have been identified in maize. Here, we identified a novel...

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Detalles Bibliográficos
Autores principales: Fan, Zhenjun, Wang, Yan, Yang, Chengshuai, Zhou, Zhihua, Wang, Pingping, Yan, Xing
Formato: Online Artículo Texto
Lenguaje:English
Publicado: KeAi Publishing 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9467860/
https://www.ncbi.nlm.nih.gov/pubmed/36158585
http://dx.doi.org/10.1016/j.synbio.2022.08.004
Descripción
Sumario:Zea mays (maize) is an important agricultural crop that produces a variety of valuable terpenoids, including several triterpenoids. However, no oxidosqualene cyclase (OSC) enzymes, which catalyze the first step in triterpenoid biosynthesis, have been identified in maize. Here, we identified a novel OSC (ZmOSC1) in maize using a combination of genomic mining and phylogenetic analyses. To functionally characterize the candidate OSC, we constructed a yeast strain that produced high levels of 2,3-oxidosqualene. When ZmOSC1 was expressed in this strain, three compounds were detected and identified as hop-17(21)-en-3-ol, hopenol B and simiarenol, respectively. For their biosynthesis, we proposed a potential cyclization mechanism catalyzed by ZmOSC1 via the generation of a dammarenyl cation, followed by sequential cationic ring expansion, cyclization, cationic migration and further proton elimination. This study discovered and characterized an OSC from maize for the first time, and laid a foundation to produce three bioactive pentacyclic triterpenes, hop-17(21)-en-3-ol, hopenol B and simiarenol, using synthetic biology approaches.